Tool for expanding and sizing the ends of metallic tubes



Jan, 3, 1950 G. E. FRANCK 294939127 1 TOOL FOR EXPANDING AND SIZING THEENDS OF METALLIC TUBES Filed July 15, 1944 NVENTOR.

GewjgeEflanci Patented Jan. 3, 1950 UNITED STATES ATENT OFFICE TOOL FOREXPANDING AND SIZING THE ENDS OF METALLIC TUBES Application July 15,1944, Serial No. 545,097

3 Claims.

my invention relates to hand service tools which are useful in expandingtubing so that a joint may be made between two pieces of tubing of thetype adapted to be sealed by means of solder or some similar sealingmaterial.

Among the objects of my invention is to provide a new and improved tubeexpanding or swaging tool which is capable of both expanding the end ofa piece of tubing and sizing the expanded portion with sufficientaccuracy over a substantial portion of its length so that when anotherpiece of tubing is inserted into it there will be a firm neat fitbetween the two.

Another object of my invention is to produce a swaging tool forexpanding tubing which utilizes only a relative minimum amount ofpressure in order to force the tube intoits expanded condition.

Still another object is to provide a new and improved swaging tool whichis so constructed that the force of friction on the part which performsthe actual work of expanding is reduced substantially to a minimum andproviding on the same tool a sizing portion which will bring theexpanded part of the tube to size without the expenditure of forcenecessary to overcome a large frictional resistance.

A further object of my invention is to provide a service tool forproducing an expanded end upon tubing by means of a swaging operationwherein the expanded end is given a uniform size over a considerablelength so that when a second length of tube is inserted the parts willnot wobble excessively one with respect to the other and will therebymake possible the production of a sweated joint which is strong andserviceable.

Still a further object is to produce a small and convenient hand servicetool which can be used to expand the ends of tubing with relative easeand which is so constructed that it can be used with equal ease andadaptability for making expanded joints on several different sizes oftubing.

With these and other objects in view, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice whereby the objects contemplated are attained, as hereinaftermore fully set forth, pointed out in my claims and illustrated in theaccompanying drawings, in which:

Figure 1 is an end view partly in section showing a hand service toolincorporating the novel features of my device.

Figure 2 is a top view partly in section taken on the line 22 of Figure1.

Figure 3 is an enlarged sectional view of the expanding member of mydevice shown in position at the end of a tube which is to be expandedand taken on the line 33 of Fig. 2.

Figure 4 is a longitudinal elevation shown with the expanding member ina position driven partly into the end of a tube, with the tube shown inlongitudinal section.

Figure 5 is a view showing the expanding member in elevation driven allof the way into a tube shown in longitudinal section.

Figure 6 shows a longitudinal section of the expanded end of the tube.

Figure 7 shows a longitudinal section of a joint made by use of theexpanded tube.

Figure 8 is an elevational view of the joint shown in Figure 7.

In order to make a tight sweated joint for thin walled tubing such ascopper tubing it is highly desirable to have the expanded end of thetubing made to such a size that it will snugly engage a length of tubinginserted into it over a considerable portion of the joint. The moresnugly the fit is made the less freely the parts will wobble one withrespect to the other and with wobbling reduced to substantially aminimum it is much easier for a mechanic to hold the parts in properrelationship until the sweated joint is completed and the solderhardened in place.

In swaging tools which have been developed in the past it has beencommon practice to make the outside diameter of the expanding portion ofthe die the same diameter which the inside diameter of the expandedportion is expected to have. This means making the diameter of theexpanding part of the die the same as that of the outside of the tubingwhich is used.

In actual practice it has been found that as a tube stretches outwardlyunder the force of expansion it has a tendency and does actually stretchto such an extent that the diameter of the expanded portion immediatelyadjacent the expanding part of the die is actually greater than thediameter of the die. This may result by reason of the particular flowcharacteristics of a ductile metal which is being shaped. However, eventhough the initial expansion may be greater than desired, as expansioncontinues and the expanding part penetrates further into the end of thetube the edge of the tube which has been expanded turns inwardly againuntil it attains a diameter about equal to the diameter of the expandinpart of the die. This return to size occurs on the free end of thetubing and to a lesser extent on the remaining part and the expandedportion instead of having a cylindrical shape fitting snugly around thetube has a close fit only at the very end. As a result the remaininglength of the expanded portion of the tubing is slightly greater indiameter than the outside diameter of the tubing at all points betweenthe outside end and the part immediately adjacent the expanding part ofthe die. The diameter is usually greatest immediately beyond theexpanding part of the die so that the enlarged end of the tube issomewhat wedge-shaped.

When the tube is expanded in the fashion just described there is a snugfit only at the very end of the expanded portion and the remaining partsof the expanded portion, being slightly oversized, will provide arelatively loose fit for the tubing inserted therein thereby permittingthe parts to wobble one with respect to the other making it difiicult toproperly freeze a sweated joint. This invention is directed to a meansof producing a snugly fitting expanded end on a tube which has acylindrical shape, rather than being wedgeshaped in section, for asubstantial portion of its length and which is so sized that thecylindrical portion at all points will snugly engage the outside of atube of the same nominal size.

In the drawings there is shown a pair of tube clamping blocks l and I2here having a length long enough to be considered as bars. The bars areeach provided with semicircular tube holding recesses 14 and I6. Thesebars may be held together at the ends in clamped position upon a lengthof tubing Is by means of bolts and 22 swivelly mounted at the ends ofone of the bars and held in position in a hole or slot in the other barby wing nuts 24 in a well-known manner. As shown in Figure 2 the barsare provided with additional recesses 28, 29, and 3| to accommodatetubes of various sizes.

A yoke 32 is provided having legs 34 and 3B which extend to a positionadjacent the clamping bars and the legs may be provided with footelements 38 and 40 adapted to engage the underside of the clamping bars.

At the end of the yoke opposite from the foot elements there is provideda threaded aperture 42 and a threaded shaft M mounted in the aperture.The shaft has a head 36 and a handle 48 extending crosswise and adaptedto rotate the shaft to move it down or up.

The actual swaging or expanding is performed by means of a die so whichhas a threaded upper end 52 designed to engage a threaded collar 54. Theshaft 44 at its lower end is provided with an annular recess 56 designedto receive a split ring 58 thereby providing a means for swivellysecuring the threaded collar upon the lower end of the shaft.

The die is provided with an axially extending recess 50 having a slopingbottom '62 and the shaft is provided with a substantially cylindricalthrust element 64 fitting loosely in the recess and having a sloping end65 designed to fit into the bottom of the recess in order to take up thethrust between the die and shaft. At its lower end as viewed in Figures1, 3, 4 and 5, the die is provided with a pilot portion 61 having adiameter slightly less than the minimum inside diameter of the tubing l8which is to be expanded. By keeping the pilot slightly smaller the dieis free to center itself in position in the end of the tube. Likewise byreason of a loose fit between the shaft and the recess in the die astraight line thrust can 'be given the die even though the shaft may notbe in precise alignment.

Adjacent the .pilot portion 61 is an annular rounded bead 68 theoutermost circumference 69 of which is slightly less than the outsidediameter of the tubing although the difference may be a matter of only avery small fraction of an inch. This bead, moreover, as seen in thedrawings, has a small radius of curvature, preferably less thanfive-thirty-seconds of an inch. A bead of small radius is employed forit makes for minimum area of contact with the tubing and thus forminimum frictional force resisting movement of the die into the tubing.It has been found that the frictional force can and does play atremendous part in the relative difficulty or ease with which a swagingtool can be forced into a .piece of tubing. A bead of small radius isemployed for the further reason that it forms a distinct shoulder in thetubing serving as a stop limiting the extent that a piece of tubing maybe inserted into the expanded end.

Adjacent the bead on the side opposite the pilot portion is an annularrecess 10, the width of which is not critical but which should be aboutthe proportion shown in Figures 3, 4, and 5.

The die is further provided with a relatively wide cylindrical sizingportion 12 immediately adjacent the recess which is substantially thesize of the outside diameter of the tubing and which will give analready expanded end ll of a piece of tubing its proper size. A shoulder14 prevents the die from being screwed too far into the threaded collar.

In operation a length of tube of the proper size is first clampedbetween the clamping bars as shown in Figures 1 and 2 with a substantialpart of the tube protruding above the bars. With the tube in place theyoke 36 is then slid over the bars until the die is centered above theopen end of the tube. The threaded shaft 4 3 is screwed downwardly untilthe pilot portion 6! enters the tube as shown in Figure 3.

Then as more pressure is exerted upon the handle the die is thrust intothe end of the tube. When this occurs the annular rounded bead graduallyworks the wall of the tubing outwardly into its expanded position asshown in Figure 4. Since only a line contact is present between therounded perimeter of the bead and the tubing only a relatively lightforce need be exerted to drive the die through an expanding operation.The tube adjacent the rounded bead may expand slightly beyond theoutside diameter of the bead and there will be no restriction to itsmovement after it expands beyond the bead because the end will then beadjacent the recess 10. The expanded portion of the tubing tends to takea slightly bowed or wedge-shaped form with the end 16 initially spread,and later drawn inwardly to the diameter of the annular head which givesit its expanded size. The cylindrical sizing portion then enters the endof the expanded tube and irons out and resizes the expanded end of thetube thereby bringing the expanded 'end of the tube to its proper sizeover a 'substantial portion of its length.

After the expanding operation has been completed the tube end H willhave the shape shown in Figured. This means that the upper end 16 willhave the same inside diameter as the outside diameter of the tube andthat a considerable portion of the length of the expanded part will haveprecisely the same diameter given to it by the sizing portion 12. Thisis a diameter whichsnugly encompasses the outside wall of a tube 18which is inserted into it. The tube can be pressed into the expanded enduntil it abuts a shoulder 80 in the expanded portion where the tubechanges size. When the tube length is thus inserted it is supported overa substantial part of its area of contact and at the end where it abutsagainst the expanded portion.

With the parts 80 and 18 thus snugly engaging each other it is possiblefor a mechanic to flow solder into the space between the tube partswithout having them wobble out of place while the solder is setting andunder those circumstances the solder will freeze the parts in properalignment.

There has thus been provided a hand service tool which by utilizing arounded bead-shaped expansion element provides a tool which can bequickly and easily driven into the end of a piece of tubing with theexpenditure of a relatively minimum amount of pressure and providesfurther a tool which will properly size the expanded end. Theeffectiveness of the tool thus provided is further enhanced by theprovision of what is in effect a thrust bearing between the shaft andthe die thereby permitting the die to remain rotatably fixed while theshaft is rotated to force it through a swaging operation.

Some changes may be made in the construction and arrangement of theparts of my device without departing from the real spirit and purpose ofmy invention, and it is my intention to cover by my claims any modifiedforms of structure, or use of mechanical equivalents, which may bereasonably included within their scope.

I claim as my invention:

1. A die for uniformly expanding and sizing an end of a piece of tubingto a size sufficient to permit insertion of an end of tubing of the samenominal tube size having at the end first to be inserted into the tubinga cylindrical pilot portion of a diameter just smaller than the insidediameter of the tubing, an annular rounded bead adjacent the pilotportion with a diameter just slightly less than the outside diameter ofthe tubing, an annular recessed portion adjacent the bead, and a sizingportion cylindrical in form and of a diameter substantially equal to theoutside diameter of the tubing.

2. A die for uniformly expanding and sizing an end of a piece of tubingtoa size sufficient to permit insertion of an end of tubing of the samenominal tube size having at the end first to be inserted into the tubinga pilot portion of a diameter smaller than the inside diameter of thetubing, an annular sharply rounded bead adjacent the pilot portionforming a distinct juncture therewith and having a diameter justslightly less than the outside diameter of the tubing, an annularrecessed portion adjacent the bead, and a sizing portion of substantialaxial dimension adjacent the recessed portion, said sizing portion beingcylindrical with a diameter substantially equal to the outside diameterof the tubing.

3. A die for uniformly expanding and sizing an end of a piece ofmetallic tubing to a size sufficient to permit insertion of an end oftubing of the same nominal tube size having at the end first to beinserted into the tubing a cylindrical pilot portion of a diameter justsmaller than the inside diameter of the tubing, an annular bead adjacentthe pilot portion, said bead having a radius of curvature not exceedingfive-thirtyseconds of an inch and a diameter just slightly less than theoutside diameter of the tubing, an annular recessed portion adjacent thebead, and a sizing portion of substantial axial dimension adjacent therecessed portion, said sizing portion being cylindrical with a diametersubstantially equal to the outside diameter of the tubing.

GEORGE E. FRANCK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 10,488 White Jan. 31, 1854123,584 Shriver Feb. 13, 1872 632,502 Monnier Sept. 5, 1899 682,250Glauber Sept. 10, 1901 1,646,384 Bergstrom Oct. 25, 1927 1,647,447I-Iartnett Nov. 1, 1927 1,850,178 Mc Chesney Mar. 22, 1932 1,886,807Heidoff NOV. 8, 1932 1,998,653 Briegel Apr. 23, 1935 2,07 ,359 DobrickMar. 2, 1937 2,132,947 Gagne Oct. 11, 1938 2,155,416 Geyer Apr. 25, 19392,278,982 Kellems Apr. 7, 1942 2,298,379 Hofiman Oct. 13, 1942 2,314,221Kellems Mar. 16, 1943 2,346,376 Heavener Apr. 11, 1944 FOREIGN PATENTSNumber Country Date 29,634 Switzerland Oct. 15, 1910

